Newly Discovered Antibody Kills Up to 91 Percent of HIV Strains

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U.S. government scientists have discovered three potent new antibodies, one of which can neutralize up to 91 percent of all HIV strains. These discoveries were published online July 8 in Science and were reported by The Wall Street Journal. Though the scientists acknowledge that their findings represent a hopeful step forward, they caution that it will take a lot of time and effort before they can be translated into something that will prevent or treat HIV infection.

Antibodies are a key element in the immune system that our body uses to defend itself from bacteria and viruses. Antibodies kill these microbes directly or flag the foreign invaders for destruction by other immune cells. Unfortunately, HIV’s outer surface is so easily changeable that antibodies—most of which can neutralize only a few strains—fail to keep it in check. This has made designing a vaccine, which works by provoking the body to produce antibodies, such a frustrating endeavor.

Following a string of failures in vaccine science, researchers have turned in recent years to a search for broadly neutralizing antibodies, which can kill multiple strains of HIV. Several have been identified, but none have been able to neutralize more than 40 percent of HIV strains, and all were quite difficult for the body to produce naturally.

The Wall Street Journal reports that, “The [new] antibodies were discovered in the cells of a 60-year-old African-American gay man, known in the scientific literature as Donor 45, whose body made the antibodies naturally. Researchers screened 25 million of his cells to find 12 that produced the antibodies.”

It’s not yet clear whether or how these new antibodies can be used to prevent and treat HIV. Researchers will focus on several possibilities. One approach entails giving the antibodies directly to people, specifically in cases to prevent transmission from mothers to their babies. Other approaches range from building traditional vaccines with the antibodies, to the developing gene therapies.

Whichever strategy is most promising, it will likely take some time before it is available. Gary Nabel, MD, PhD—one of the leaders of the studies and a director of the Vaccine Research Center at the National Institute of Allergy and Infectious Diseases in Bethesda, Maryland—told the Journal, “We’re going to be at this for a while” before any benefit is seen in the clinic.